"Why ... almost all of them."
"Earth is home," he said gently. "When men leave home they can adapt to different planets, but a price must be paid. A terrible price in dead infants. The successful mutations live, the failures die. Natural selection is a brutally simple affair. When you look at me you see a success. I have a sister—a success too. Yet my mother had six other children who died when they were still babies. And at least fifteen others that never came to term. You know these things, don't you Lea?"
"I know, I know...." she said sobbing into her hands. He held her now and she didn't pull away. "I know it all as a biologist—but I am so awfully tired of being a biologist, and top of my class and a mental match for any man. But when I think about you, I do it as a woman, and can't admit any of this. I need someone Brion, and I needed you so much because I loved you." She sniffed and pushed at her eyes. "You're going home, aren't you? Back to Anvhar. When?"
"I can't wait too long," he said, unhappily. "Aside from my personal wants I find myself remembering that I'm a part of Anvhar. When you think of the number of people who suffered and died—or adapted—so that I could be sitting here now. Well, it's a little frightening. I suppose it doesn't make sense logically that I should feel indebted to them. But I do. Whatever I do now, or in the next few years, won't be as important as getting back to Anvhar."
"And I won't be going back with you." It was a flat statement the way she said it, not a question.
"No, you won't be," he said.
Lea was looking out of the port at Dis and her eyes were dry now. "Way back in my deeply buried unconscious I think I knew it would end this way," she said. "If you think your little lecture on the Origins of Man was a novelty, it wasn't. Just reminded me of a number of things my glands had convinced me to forget. In a way I envy you your weightlifter wife-to-be, and your happy kiddies. But not very much. Very early in life I resigned myself to the fact that there was no one on Earth I would care to marry. I always had these teen-age dreams of a hero from space who would carry me off, and I guess I slipped you into the pattern without realizing it."
"Don't we look happy," Hys said, shambling towards them.
"Fall dead and make me even happier then," Lea snapped bitterly.